/*  
 * i-OSGi - Tunable Bundle Isolation for OSGi
 * Copyright (C) 2011  Sven Schulz
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.iosgi.outpost;

import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ExceptionEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Sven Schulz
 */
public class ServerHandler extends SimpleChannelUpstreamHandler {

	private static final Logger LOGGER = LoggerFactory
			.getLogger(ServerHandler.class.getName());

	@SuppressWarnings("unchecked")
	@Override
	public void messageReceived(ChannelHandlerContext ctx, MessageEvent me) {
		Object obj = me.getMessage();
		if (!(obj instanceof Operation<?>)) {
			me.getChannel().close();
		}
		Channel c = me.getChannel();
		Operation<Object> op = (Operation<Object>) obj;
		try {
			Object result = op.perform();
			if (result == null) {
				c.write(Null.NULL);
			} else {
				c.write(result);
			}
		} catch (Exception e) {
			OperationExecutionException oee = new OperationExecutionException(e);
			c.write(oee);
		}
	}

	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) {
		LOGGER.warn("Unexpected exception from downstream.", e.getCause());
		e.getChannel().close();
	}
	
}